A package having an opening covered with a lid is used for housing an electronic component, such as an acceleration sensor chip, an angle speed sensor chip, and a surface acoustic component. The electronic component is constructed of elements formed on chip surfaces with a few μm orders of fine structures that are processed by micromachining technique. The electronic component is inserted into a body of the package through the opening, provided on one of the sides of the package body.
A package of such a kind is proposed in US2001/55836 (JP-A-2002-005951). A semiconductor dynamic sensor chip having a comb-teeth-like structure is included in the package. The sensor chip is mounted on a ceramic package case and a metal lid is seam-welded to the package case. To make the seam-welding of the lid easier, surfaces of the lid may be plated.
When the lid is plated, plating films are formed on its surfaces. Burrs (dross) of a few μm to tens of μm develop on or adhere to the plating films. A plating film is formed on a surface of the lid and hangnail-like burrs are formed on the surface of the plating film. The burrs may develop around waste metals that exist in the plating tank and adhere to the surface of the lid during the plating process.
A sensor chip housed in such a package body, for instance one in US2001/55836, has a few μm orders of movable structures on its surfaces. If burrs formed on the lid surface fall on the movable structure during a transfer of the chip, the characteristics of the sensor chips may be affected by the burrs. The same problems could occur in other electronic devices if they are provided with plated lids and electronic components having similar movable structures are housed in the packages. The electronic components having such movable structures include an angle speed sensors and a surface acoustic component. This burr problem could be a common problem among packages having a plated lid.